The purpose of the study of two sets of infant twins, where one infant of each set was severely handicapped, was to investigate the effect of a handicapping condition on mother-infant interactions and to investigate the conditions under which coordinated attention to an object and a person is demonstrated. This study provided a unique opportunity…

Stability of child and mother characteristics and the predictability of children's cognitive competence and affective characteristics were investigated as part of a longitudinal study. At 2 years of age, 46 sets of male twins and their parents were observed in the home and were rated for attachment, independence, compliance and conscience on the…

Drawings designed by three identical and three fraternal, normal, 6- and 7-year-old twin pairs are inspected for signs of a struggle for individual identity. Each twin must go through the process of becoming aware of him/herself as separate from the mother and must individuate from his/her twin as well. Interdependence may retard maturation. In…

RESEARCH ON HEREDITARY FACTORS IN NORMAL PERSONALITY TRAITS, AS MEASURED BY INVENTORIES, HAS BEEN LIMITED BY THE FOLLOWING FACTORS--(1) DATA DRAWN FROM ADOLESCENT, NOT ADULT, TWINS, (2) OMISSION OF MENTALLY ILL TWINS, (3) SMALL SIZE OF SAMPLES, (4) VARIABILITY STUDIED ONLY WITHIN FAMILY, (5) SMALL, ISOLATED, UNCOORDINATED STUDIES, AND (6) PROBLEMS…

The first study presented here looks at the effects of years of schooling on earnings and assesses how much earnings and years of schooling are attributable to inequality of opportunity. The second study examines the effects of schooling on health. The first study examined a sample of approximately 1,000 pairs of identical twins and 900 pairs of…

The purposes of this study were a) to investigate the relationship between grip strength and the measures of age, height, weight, and the personality traits revealed by the Comrey Personality and Attitude Factor Scales and b) to assess the influence of heredity on height, weight, and grip strength. Fifty-eight pairs of twins (MZ, 30 and DZ, 28)…

Fifteen monozygotic and 22 dizygotic twin pairs, who were found to be lower in verbal ability than matched singletons at age two years, were compared at age nine years. Although twins still showed lower verbal ability, more variance in verbal ability was accounted for by the mothers' education and birth weight than by being a twin. (SLD)

Reviews current research on a woman's chances of bearing twins and the genetic relationship, prenatal competition, and personality similarities between twins. In addition, the nature/nurture controversy is discussed in terms of evidence from studies of identical twins reared apart. Future studies are suggested to discover the ways twinning might…

Assessed temperament of newborn twins using comprehensive neonatal exam that focused on irritability, resistance to soothing activity, and reinforcement value. Some infants were later assessed at 9 months. Emotional activity appeared to be core dimension stretching over ages and is discussed in relation to formulations of infant temperament.…

Mothers of 232 pairs of twins were interviewed periodically about the similarities and differences in behavior displayed by their twins during infancy and early childhood. (Authors)

Discusses basic concepts in human and medical genetics and their relevance to the field of adoption. Describes genetic counseling and suggests that adoption agencies use such services. (Author)